Zwitterionic Ligand Research Articles

Enhancing the quantum yield and stability of CsPbBr3 quantum dots with zwitterionic ligand post-treatment

The poor stability and low photoluminescence quantum yield (PLQY) of halide perovskite quantum dots (QDs) have been major challenges for their future practical application. Ligand engineering has been demonstrated as an effective approach for enhancing both stability and PLQY. Herein, we introduce a zwitterionic ligand, specifically N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (TDPS), to synthesize stable CsPbBr3 QDs by ligand post-treatment. The as-prepared TDPS-QDs exhibited an exceptional PLQY of 86.5 % and superior colloidal stability when exposed to UV light, heat, and polar solvents, owing to surface defect passivation and strong affinity to the surfaces. The PL intensity of TDPS-QDs maintains approximately 68 % (120 min) and 103 % (48 h) of its initial emission intensity under continuous irradiation or heat, respectively, whereas OA-QDs (pristine CsPbBr3 QDs) undergo greater quenching within a shorter period. The findings highlight the potential for TDPS ligand modification to simultaneously improve the QY and stability, thus opening novel avenues for future applications involving CsPbBr3 QDs.

Assessing the Steric Impact of Surface Ligands on the Proteolytic Turnover of Quantum Dot-Peptide Conjugates.

Proteases are important biomarkers and targets for the diagnosis and treatment of disease. The advantageous properties of semiconductor quantum dots (QDs) have made these nanoparticles useful as probes for protease activity; however, the effects of QD surface chemistry on protease activity are not yet fully understood. Here, we present a systematic study of the impact of sterics on the proteolysis of QD-peptide conjugates. The study utilized eight proteases (chymotrypsin, trypsin, endoproteinase Lys C, papain, endoproteinase Arg C, thrombin, factor Xa, and plasmin) and 41 distinct surface chemistries. The latter included three molecular weights of each of three macromolecular ligands derived from dextran and polyethylene glycol, as well as anionic and zwitterionic small-molecule ligands, and an array of mixed coatings of macromolecular and small-molecule ligands. These surface chemistries spanned a diversity of thicknesses, densities, and packing organization, as characterized by gel electrophoresis, capillary electrophoresis, dynamic light scattering, and infrared spectroscopy. The macromolecular ligands decreased the adsorption of proteases on the QDs and decelerated proteolysis of the QD-peptide conjugates via steric hindrance. The properties of the QD surface chemistry, rather than the protease properties, were the main factor in determining the magnitude of deceleration. The broad scope of this study provides insights into the many ways in which QD surface chemistry affects protease activity, and will inform the development of optimized nanoparticle-peptide conjugates for sensing of protease activity and resistance to unwanted proteolysis.

Origin of Water-Stable CsPbX3 Quantum Dots Assisted by Zwitterionic Ligands and Sequential Strategies for Enhanced Luminescence Based on Crystal Evolution.

Water stability is a crucial issue always addressed for commercial practical application of perovskite quantum dots (QDs). Recent advances in ligand engineering for in situ synthesis of water-stable perovskite QDs have attracted growing interest. However, the exact mechanism remains unclear. Here, the function of 4-bromobutyric acid (BBA) and oleylamine (OLA) is systematically studied in water-stable CsPbX3 (X = Br and I) QDs and confirms that the zwitterionic ligands generated in situ by BBA and OLA are anchored on the QDs surface, thus preventing water from penetrating into the QDs. Cs4PbBr6 intermediate crystal found in the crystal structure evolution process of CsPbX3 QD further reveals a complete crystallization process: PbX2 + CsX + Br- → Cs4PbBr6 crystals + X-→ CsPbX3 QDs + Br-. Furthermore, it is found that the solvent coordination of the precursor solution has a significant effect on the crystallinity of Cs4PbBr6 intermediate crystal, while the Rb+ doping can effectively passivate the surface defects of CsPbX3 QDs, thereby jointly achieving photoluminescence quantum yields (PLQY) of 94.6% for CsPbBr3 QDs (88.2% for CsPbI3 QDs). This work provides new insights and guiding ideas for the green synthesis of high-quality and water-stable perovskite QDs.

Light/pH dual-responsive magnetic metal-organic frameworks composites for phosphorylated peptide enrichment

Metal-organic frameworks (MOFs) combined with specific ligands are highly adaptable smart materials that can respond to external and physiological stimuli. In this study, we introduced a pyridinyl zwitterionic ligand with light/pH dual response into magnetic MOF composite (Fe3O4@ZW-MOF) for enrichment of phosphorylated peptides for the first time. The introduction of the developed ligand gives MOF material dual response properties. Light stimulation affects the generation/disappearance of free radicals of the pyridine derivative, resulting in a change in the charge gradient of the zwitterion, and zwitterion can also regulate the pH of the solution by adding acid or base. Therefore, the reversible capture and release of phosphorylated peptides can be easily achieved by adjusting light and pH. The established phosphorylated peptide enrichment platform exhibits high sensitivity (detection limit of 1 fmol), high selectivity (β-casein:BSA, 1:1000), and good reusability (7 cycles). In addition, the method was applied to the enrichment of phosphorylated peptides in complex systems (non-fat milk and human serum), demonstrating the feasibility of this method for phosphoproteom analysis. In conclusion, the synthesized Fe3O4@ZW-MOF is a promising MOF material, which provides the possibility to advance the application of responsive MOFs materials in proteomics.

Highly sensitive fluorescence detection of tetracycline in food samples using a Zn5 cluster-based zwitterionic metal-organic framework

A brilliantly stable and luminescent Zn5-cluster-based metal-organic framework, namely {[Zn5(bci)4(OH)2(SO4)2]·4H2O} (MOF 1), was successfully constructed by zwitterionic ligand H2bciCl (1,3-bis(4-carboxybenzyl)-1H-imidazol-3-ium chloride) in solvothermal condition. MOF 1 which crystallized in tetragonal crystal system P41212 space group with 8-connected bcu body-centered-cubic topology exhibits excellent organic solvent stability, water stability, and pH stability. As a new fluorescence sensor, MOF 1 can selectively, sensitively, rapidly and recyclably detect tetracycline (TCY) antibiotic in aqueous solution through fluorescence quenching effect with a low detection limit of 0.083 μM. Additionally, as a fluorescent detection material with potential practical application value, MOF 1 is able to detect TCY in chicken, egg and fish samples with excellent recovery rates. The reasonable fluorescent detection mechanism has been confirmed, which may be a combination of fluorescence resonance energy transfer (FRET) and photoelectron electron transfer (PET).

Imidazol(in)ium-2-Thiocarboxylate Zwitterion Ligands: Structural Aspects in Coordination Complexes

Azolium-2-thiocarboxylate zwitterion ligands have emerged as a promising class of compounds in the field of coordination chemistry due to their unique structural features and versatile applications. These ligands are characterized by a positively charged azolium ring and a negatively charged thiocarboxylate moiety, making them capable of forming stable coordination complexes with various metal ions. One of the key structural aspects that make these ligands attractive for coordination chemistry is their ability to adopt diverse coordination modes with metal centers. The nature of these ligands enables them to engage in both monodentate and bidentate coordination, resulting in the formation of chelated complexes with enhanced stability and controlled geometry or the formation of polynuclear structures. This versatility in coordination behavior allows for the design of tailored ligands with specific metal-binding preferences, enabling the creation of unique and finely tuned coordination architectures. The azolium-2-thiocarboxylate zwitterionic ligands offer a promising platform for the design of coordination complexes with diverse structural architectures.

Tuning Ligands Ratio Allows for Controlling Gold Nanocluster Conformation And Activating A Nonantimicrobial Thiol Fragrance for Effective Treatment of MRSA-induced Keratitis.

Bacterial keratitis is a serious ocular disease that affects millions of people worldwide each year, among which ∼25% are caused by Staphylococcus aureus. With the spread of bacterial resistance, refractory keratitis caused by methicillin-resistant Staphylococcus aureus (MRSA) affects ∼120-190 thousand people annually and has become a significant cause of infectious blindness. Atomically precise gold nanoclusters (GNCs) have recently emerged as promising antibacterial agents, although how GNC structure and capping ligands control its antibacterial properties remain largely unexplored. In this study, by adjusting the ratio of a "bulky" thiol fragrance to a linear zwitterionic ligand, the GNC conformation is transformed from Au25 (SR)18 to Au23 (SR)16 species, simultaneously converting both inactive thiol ligands into potent antibacterial nanomaterials. Surprisingly, mixed-ligand capped Au23 (SR)16 GNCs exhibit superior antibacterial potency compared to their mono-ligand counterparts. The optimal GNC is highly potent against MRSA, showing >1024-fold lower minimum inhibitory concentration than the corresponding free ligands. Moreover, it displays excellent potency in treating MRSA-induced keratitis in mice with greatly accelerated corneal recovery (by ∼9-fold). Thus, this study establishes a feasible method to synthesize antibacterial GNCs by adjusting the ligand ratio to control GNC conformation and active non-antibacterial ligands, thereby greatly increasing the repertoires for combating multidrug-resistant bacterial infections. This article is protected by copyright. All rights reserved.

Synthesis of Zwitterionic CsPbBr3 Nanocrystals with Controlled Anisotropy using Surface-Selective Ligand Pairs.

Mechanistic studies of the morphology of lead halide perovskite nanocrystals (LHP-NCs) are hampered by a lack of generalizable suitable synthetic strategies and ligand systems. Here, the synthesis of zwitterionic CsPbBr3 NCs is presented with controlled anisotropy using a proposed "surface-selective ligand pairs" strategy. Such a strategy provides a platform to systematically study the binding affinity of capping ligand pairs and the resulting LHP morphologies. By using zwitterionic ligands (ZwL) with varying structures, majority ZwL-capped LHP NCs with controlled morphology are obtained, including anisotropic nanoplatelets and nanorods, for the first time. Combining experiments with density functional theory calculations, factors that govern the ligand binding on the different surface facets of LHP-NCs are revealed, including the steric bulkiness of the ligand, the number of binding sites, and the charge distance between binding moieties. This study provides guidance for the further exploration of anisotropic LHP-NCs.

One-Step Ultrasonic Preparation of Stable Bovine Serum Albumin-Perovskite for Fluorescence Analysis of L-Ascorbic Acid and Alkaline Phosphatase.

Halide lead perovskite has attracted increased attention due to its excellent optical properties. However, the poor stability of the halide lead perovskite nanocrystals has been a major obstacle to their application in biosensing. Here, we proposed a method to synthesize CsPbBr3/BSA NCs perovskite using bovine serum albumin (BSA) as a zwitterion ligand. Then, a fluorescent sensor for alkaline phosphatase determination based on CsPbBr3/BSA NCs was successfully built via the interaction of L-ascorbic acid (AA) with BSA on the perovskite surface. Under optimal conditions, the sensor showed a linear concentration range from 50 to 500 μM with a detection limit of 28 μM (signal-to-noise ratio of 3) for AA, and demonstrated a linear concentration range from 40 to 500 U/L with a detection limit of 15.5 U/L (signal-to-noise ratio of 3) for alkaline phosphatase (ALP). In addition, the proposed fluorescent biosensor exhibited good selectivity and recovery in the determination of ALP in human serum. This strategy offers an innovative way for enhancing the water stability of lead halide perovskite and promoting their application in biosensing areas.

Zwitterionic Carbazole Ligands Enhance the Stability and Performance of Perovskite Nanocrystals in Light-Emitting Diodes.

We introduce a new carbazole-based zwitterionic ligand (DCzGPC) synthesized via Yamaguchi esterification which enhances the efficiency of lead halide perovskite (LHP) nanocrystals (NCs) in light-emitting diodes (LED). A facile ligand exchange of the native ligand shell, monitored by nuclear magnetic resonance (NMR), ultraviolet-visible (UV-vis), and photoluminescence (PL) spectroscopy, enables more stable and efficient LHP NCs. The improved stability is demonstrated in solution and solid-state LEDs, where the NCs exhibit prolonged luminescence lifetimes and improved luminance, respectively. These results represent a promising strategy to enhance the stability of LHP NCs and to tune their optoelectronic properties for further application in LEDs or solar cells.

Zwitterions Functionalized by Optical Cycling Centers: Toward Laser-Coolable Polyatomic Molecular Cations.

Functionalization of large aromatic compounds and biomolecules with optical cycling centers (OCC) is of considerable interest for the design and engineering of molecules with a highly selective optical photoresponse. Both internal and external dynamics in such molecules can be precisely controlled by lasers, enabling their efficient cooling and opening up broad prospects for high-precision spectroscopy, ultracold chemistry, enantiomer separation, and various other fields. The way the OCC is bonded to a molecular ligand is crucial to the optical properties of the OCC, first of all, for the degree of closure of the optical cycling loop. Here we introduce a novel type of functionalized molecular cation where a positively charged OCC is bonded to various organic zwitterions with a particularly high permanent dipole moment. We consider strontium(I) complexes with betaine and other zwitterionic ligands and show the possibility of creating efficient and highly closed population cycling for dipole-allowed optical transitions in such complexes.

Photocrosslinkable Zwitterionic Ligands for Perovskite Nanocrystals: Self‐Assembly and High‐Resolution Direct Patterning

AbstractPerovskite nanocrystals (PNCs) are attractive photoactive materials in various optoelectronic devices including light‐emitting diodes, solar cells, and photodetectors. However, the weakly bound surface ligands on PNCs reduce colloidal stability and cause film formation and patterning difficulties, severely restricting their practical applications. Herein, a rationally designed photocrosslinkable zwitterionic (PZ) ligand is introduced to obtain directly patternable CsPbBr3 PNCs with enhanced colloidal stability, optical properties, and self‐assembly propensity. The PZ ligands strongly interact with the pre‐synthesized PNCs in solution, substantially replacing the original capping ligands and effectively passivating surface defects. This surface engineering induces strong electrostatic interactions between the PNCs, enabling the fabrication of densely packed CsPbBr3 PNC films. Furthermore, the methacrylate group of the PZ ligands serves as a bridge for active radical propagation in the ligand shells around the PNCs upon UV exposure. Accordingly, high‐resolution direct photopatterning can be achieved through ligand crosslinking, and the resulting PNC patterns (minimum line spacing of 4 µm) maintain optical stability for over 2 weeks. Therefore, this study demonstrates that a tailored ligand design strategy enables the simultaneous achievement of high colloidal stability, optical properties, photopatternability, and self‐assembly propensity and has considerable potential to be extended to other PNC materials.

Host–Guest Symmetry and Charge Matching in Glycine-Templated Metal Sulfate–Oxalates Obtained by a Solvent-Free Method

Two metal sulfate-oxalates, (Hgly)2·Zn(SO4)(C2O4) (1) and Hgly·In(SO4)(C2O4)(gly) (2), were prepared under solvent-free conditions, where gly = glycine. They have similar layered structures despite the fact that aliovalent metal ions are used as structural nodes. Notably, glycine molecules play dual roles as a protonated cation and a zwitterionic ligand in compound 2. The two compounds display moderate second-harmonic-generation (SHG) responses, confirming their noncentrosymmetric structures. Theoretical calculations were performed to reveal the origin of their SHG responses.

Flexible Aliphatic Diammonioacetates as Zwitterionic Ligands in UO22+ Complexes: Diverse Topologies and Interpenetrated Structures.

N,N,N',N'-Tetramethylethane-1,2-diammonioacetate (L1) and N,N,N',N'-tetramethylpropane-1,3-diammonioacetate (L2) are two flexible zwitterionic dicarboxylates which have been used as ligands for the uranyl ion, 12 complexes having been obtained from their coupling to diverse anions, mostly anionic polycarboxylates, or oxo, hydroxo and chlorido donors. The protonated zwitterion is a simple counterion in [H2L1][UO2(2,6-pydc)2] (1), where 2,6-pydc2- is 2,6-pyridinedicarboxylate, but it is deprotonated and coordinated in all the other complexes. [(UO2)2(L2)(2,4-pydcH)4] (2), where 2,4-pydc2- is 2,4-pyridinedicarboxylate, is a discrete, binuclear complex due to the terminal nature of the partially deprotonated anionic ligands. [(UO2)2(L1)(ipht)2]·4H2O (3) and [(UO2)2(L1)(pda)2] (4), where ipht2- and pda2- are isophthalate and 1,4-phenylenediacetate, are monoperiodic coordination polymers in which central L1 bridges connect two lateral strands. Oxalate anions (ox2-) generated in situ give [(UO2)2(L1)(ox)2] (5) a diperiodic network with the hcb topology. [(UO2)2(L2)(ipht)2]·H2O (6) differs from 3 in being a diperiodic network with the V2O5 topological type. [(UO2)2(L1)(2,5-pydc)2]·4H2O (7), where 2,5-pydc2- is 2,5-pyridinedicarboxylate, is a hcb network with a square-wave profile, while [(UO2)2(L1)(dnhpa)2] (8), where dnhpa2- is 3,5-dinitro-2-hydroxyphenoxyacetate, formed in situ from 1,2-phenylenedioxydiacetic acid, has the same topology but a strongly corrugated shape leading to interdigitation of layers. (2R,3R,4S,5S)-Tetrahydrofurantetracarboxylic acid (thftcH4) is only partially deprotonated in [(UO2)3(L1)(thftcH)2(H2O)] (9), which crystallizes as a diperiodic polymer with the fes topology. [(UO2)2Cl2(L1)3][(UO2Cl3)2(L1)] (10) is an ionic compound in which discrete, binuclear anions cross the cells of the cationic hcb network. 2,5-Thiophenediacetate (tdc2-) is peculiar in promoting self-sorting of the ligands in the ionic complex [(UO2)5(L1)7(tdc)(H2O)][(UO2)2(tdc)3]4·CH3CN·12H2O (11), which is the first example of heterointerpenetration in uranyl chemistry, involving a triperiodic, cationic framework and diperiodic, anionic hcb networks. Finally, [(UO2)7(O)3(OH)4.3Cl2.7(L2)2]Cl·7H2O (12) crystallizes as a 2-fold interpenetrated, triperiodic framework in which chlorouranate undulating monoperiodic subunits are bridged by the L2 ligands. Complexes 1, 2, 3, and 7 are emissive with photoluminescence quantum yields in the range of 8-24%, and their solid-state emission spectra show the usual dependence on number and nature of donor atoms.

Eco-friendly Solvent-Processible and highly luminescent perovskite nanocrystals with polymer zwitterions for Air-Stable optoelectronics

Perovskite quantum dots (QDs) have been studied as building blocks for next-generation optoelectronics owing to the wide tunability of their crystal structure and shape. One of the greatest hurdles for perovskite QDs is material instability when exposed to water, heat and polar solvents. Furthermore, the toxicity of solvents used for perovskite materials can lead to hazardous solution processes, unfavourable for large-area processes. In this paper, we report a perovskite surface engineering technique using zwitterionic polymer ligands, poly(carboxybetaine acrylamide) (PCA), to produce ultrastable perovskite QDs in polar solvents. We demonstrate that PCA polymers have a strong binding energy on the perovskite surface as coordinate bonds, according to experimental data and density functional theory (DFT) calculations. Moreover, the QDs produced with PCA maintained photoluminescence stability for over 50 d and uniform dispersion in alcohol solvents, which shows potential for an eco-friendly processability. Finally, we developed a band-gap-tuned white light-emitting diode (WLED) and produced roll-to-roll-processed thin films using slot-die coating.

Binuclear azide-bridged hydrazone Cu(II) complex: Synthesis, characterization and evaluation of biological activity

The condensation product of 7-acetyl-6-azaindole and Girard?s T reagent ((E)-2-(2-(1-(1H-pyrrolo[2,3-c]pyridin-7-yl)ethylidene)hydrazineyl)- -N,N,N-trimethyl-2-oxoethan-1-aminium, HL ligand) was used as a ligand in the reaction with Cu(BF4)2?6H2O and NaN3. The reaction led to the formation of a binuclear Cu(II) complex containing two end-to-end (di-?-1,3-N3) azide bridges, as well as two NNO-donor hydrazone ligands, forming an axially elongated square pyramidal geometry around each Cu(II) center. This end-to-end (di- ?-1,3-N3) azide bridge binding mode has not yet been reported, in Cu(II) complexes containing the NNO-donor hydrazone ligands, which makes the structure of the complex even more interesting for further studies. The complex was characterized by elemental analysis, IR spectroscopy and X-ray crystallography, and it was found that it crystallizes in the triclinic space group P?1 with the asymmetric unit comprising one Cu(II) centre, zwitterionic ligand L, one azide (N3 -) ligand and BF4 - counter anion. Examination of antimicrobial activity of the complex shows higher antifungal and antibacterial activity towards tested Gram-positive bacteria in comparison to the hydrazone ligand, with the antifungal activity of the complex even being comparable to the activity of amphotericin B.

High Water-Assisted Proton Conductivities of Two Cadmium(II) Complexes Constructed from Zwitterionic Ligands.

Finding more metal complexes with outstanding water stability and high proton conductivity still has important research significance for the energy field. Herein, two highly proton-conductive complexes, one hydrogen-bonded supramolecular framework (HSF) [Cd(CBIA)2(H2O)4]·2H2O (1) and one coordination polymer (CP), {[Cd2(CBIA)2(4,4'-bipy)2(H2O)2]·(CBIA)·(OH)·2H2O}n (2) (4,4'-bipy = 4,4'-bipyridine), were triumphantly assembled using a zwitterionic organic compound, 2-(1-(carboxymethyl)-1H-benzo[d]imidazol-3-ium-3-yl)acetate (HCBIA). In the structure of HSF 1, there are several coordination and lattice H2O units except for the two monodentate CBIA- anions. CP 2 with a one-dimensional (1D) cylindrical structure has free CBIA- units and free H2O units located in the cavity. Thanks to the ability of the uncoordinated carboxyl groups and coordination/lattice water molecules to construct the rich H-bonding networks, both complexes exhibit super-high proton conductivities, reaching 5.09 × 10-3 and 3.41 × 10-3 S cm-1 under 100 °C/98% relative humidity (RH), respectively. Based on the exploration of crystal structure data, combined with the calculated activation energy, and adsorption/desorption plots of nitrogen and water vapor, the causes and differences in proton conductivity of the two complexes, especially the proton-conductive mechanism, are compared and analyzed. This study again confirms that the zwitterionic ligands can exert important effects on forming organo-inorganic hybrid materials with high proton conductivity.

A water-stable zwitterionic Cd(II) coordination polymer as fluorescent sensor for the detection of oxo-anions and dimetridazole in milk

Coordination polymers (CPs) constructed by zwitterionic ligands show obvious advantages in the fluorescence sensing of toxic pollutants due to the separated charge centers on the frameworks, where the construction of aqueous-phase stable and multifunctional complexes is crucial for practical applications in environmental or food safety detection. A Cd(II) 2D water-stable porous CPs {[CdL(H2O)2]·(ClO4)·3H2O} (1) (flexible H2LCl = 5-carboxy-1-(4-carboxybenzyl)-2-methylpyridin-1-ium chloride) was solvothermally synthesized from good fluorescent zwitterionic organic linkers and was further characterized by single-crystal X-ray diffraction, Hirshfeld surface analysis, powder X-ray diffraction (PXRD), IR spectra, elemental analysis, and thermogravimetric analysis (TG). Aqueous-phase sensing studies demonstrate that complex 1 can serve as a unique bifunctional luminescent probe for highly selective, quick responsive and multicyclic detection of three noxious high-valent oxo − anions Cr2O72−, CrO42−, MnO4− as well as dimetridazole (DTZ) antibiotic via remarkable fluorescence quenching with low limits of detection (LODs) (Cr2O72− 0.12 μM, CrO42− 0.16 μM, MnO4− 0.29 μM and DTZ 0.09 μM). Moreover, the sensor has a certain practical application potential. It obtains desirable recoveries (96.10–105.35 %) for the determination of oxo-anions and DTZ in milk, respectively. Mechanism for all the turn-off responses between the framework and analytes were elaborately explored by means of the electron transfer analytical methods and density functional theory (DFT) calculations.

Highly sensitive and rapid fluorescence detection of chlortetracycline in milk using a water- and pH-stable Zn (II) coordination polymer derived from zwitterionic and N-donor ligands

A novel and interesting Zn (II) coordination polymer, [ZnL(4,4′-bpd)(H2O)2]·(ClO4)2 (CP 1), was synthesized under hydrothermal conditions by a zwitterionic organic ligand (1,1'-((2,5-dimethyl-1,4-phenylene)bis(methylene))bis(4-carboxypyridin-1-ium)chloride (H2LCl2)) and a N-donor ligand (4,4′-bipyridine (4,4′-bpd)). Fluorescence sensing experiments showed that CP 1 preforms high selectively and sensitivity for rapid detection of Chlortetracycline (CTC) in aqueous solutions via fluorescence quenching effects and has a shallow detection limit (0.015 ​μM). In addition, The CP 1 is the first example of a fluorescent sensor that can sensitively detect CTC in milk with a perfect recovery rate of 92.97–103.83%. The possible mechanism of the fluorescence quenching mechanisms of the CP 1 was described as internal filtration effect (IFE) and photoelectron electron transfer (PET).

Morphological, structural, and photophysical properties of luminescent coordination compounds based on Eu3+ and a zwitterionic ligand: A theoretical and experimental investigation

The development of functional materials with photoluminescent properties based on coordination compounds and trivalent lanthanide ions has attracted interest from the scientific community. In this regard, two materials based on a combination of zwitterion ligand (3-(1-methylimidazolium-1-yl) butane-1-sufonate) (Z) and Eu3+ ions (EuZCrystal and EuZGel) were prepared by a simple and efficient method, and the chemical, morphological, and photophysical properties were evaluated. Nuclear Magnetic Resonance (NMR) analysis reveals a broadening and shift from EuZCrystal and EuZGel spectra relative to the Z ligand, especially for the S–O bond, which indicated that the sulfone group is the coordinating site responsible for the bond between the Z molecule and Eu3+. The emission spectra reveal the line profiles of the Eu3+ ion in the coordination compounds for EuZCrystal and EuZGel, which agree with the formation of the new luminescent material. Although the ligand → Eu3+ energy transfer rates are at least 100 times higher than the rates calculated for the Eu3+ → Eu3+ energy transfer, the experimental excitation spectrum suggests that there is not enough electron population to populate the 5D0 emitter state and its consequent decay.